20 different link together to form chains. a protein is composed of one or more of these chains which are twisted and folded into a particular shape.

Amino acids; peptide

Explanation:

20 different AMINO ACIDS link together to form chains. A protein is composed of one or more of these PEPTIDE chains which are twisted and folded into a particular shape.

There exists 20 amino acids capable of forming protein in the Human body. At least two amino acids are joined together by a peptide bond to form polypeptide chains that are then held together by hydrogen bonds in twisted alpha helical structures to form proteins.

Amino acid, polypeptide/polynucleotide chains

Explanation: Amino acids are usually the building blocks of protein hence,every protein is made up of one or more amino acids.

A protein consist of one or more polypeptide chain that is folded into a helix shape. This shape is to prevent the easy degradation of the components that makes up the polypeptide because it is water loving and can easy degrade.